Chemistry - atomic structure and the periodic table

Atom

The smallest piece of matter that exists. It is indivisible, so if you split it, it would no longer retain the characteristics of an element

Element

a substance which is made up of only one type of atom

compound

a substance which contains two or more elements chemically bonded together

If an atom gains electrons, it becomes __ charged.

negatively

If an atom loses electrons it becomes charged

positively

Atomic number

Number of protons

Number of neutrons

mass number - atomic number

Ion

an atom that has a positive or negative charge as a result of having lost or gained electrons

Metal ions are always

positive

non metal ions are usually

negative

isotope

an atom of an element with a different number of neutrons, compared to an atom of the same element